AbstractThis paper deals with a digital signal processor (DSP) based implementation of a three‐phase shunt active filter (AF) to compensate harmonics and reactive power of nonlinear loads. A three‐phase diode bridge rectifier with R‐L and R‐C loads is taken as the nonlinear load. It is observed that the AF systems suffer from the problems of switching ripples (in case of R‐L nonlinear load) and distortion (in case of R‐C nonlinear load). The switching ripples and distortion in the supply currents contribute considerably to its Total Harmonics Distortion (THD). This investigation proposes a new, cost free and simple approach for the elimination of switching ripples and distortion in the supply current. A pulse width modulation (PWM) current controlled voltage source inverter (CCVSI) is used as the AF. The AF system is tested with two types of PWM switching techniques, namely, carrier‐less (hysteresis) and carrier based techniques. Two types of current control techniques, namely, direct current control and indirect current control are designed to obtain PWM switching signals for the devices of the AF. The capability of the indirect current control technique towards the elimination of switching ripples and distortion is established. Simulated and experimental results for steady state and transient operating conditions of the AF for R‐L as well as R‐C nonlinear loads are given and discussed in detail.
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